Note: Descriptions are shown in the official language in which they were submitted.
CA 02665652 2009-05-08
STRUCTURAL INSULATING PANEL AND FLAT ROOF STRUCTURE
EMPLOYING SAME
Field of the Invention
[0001] The present invention relates generally to building structure
and in
particular, to a structural insulating panel and flat roof structure employing
the same.
Background of the Invention
[0002] Historically, flat or horizontal roofs on commercial and
residential
buildings have been common in warmer, drier climates where water accumulation
as
a result of precipitation is not a problem. More recently, flat roofs have
become
popular in cooler, wetter climates. Unlike sloped roofs, flat roofs have
ineffective
drainage characteristics making them prone to leakage problems. In wetter
climates,
to deal with this drainage issue, complex water proofing is typically required
in flat
roofs. In commercial buildings, drains are sometimes provided in the flat
roofs to
collect rainwater and melting snow and direct the water off of the roofs.
[0003] For example, U.S. Patent No. 5,144,782 to Paquette et al.
discloses a
draining system for water which may collect between the upper and lower
membranes
of a flat insulated roof. Insulating panels located between the upper and
lower
membranes are provided at both their upper and lower faces with a network of
intersecting grooves. The networks of grooves communicate with each other
through
passages made through the insulating panels or constituted at the insulating
panel
joints. The grooves and passages provide drainage channels for any water that
has
seeped under the upper membrane as a result of perforations in the upper
membrane.
A lower drain is sealed to and opens above the lower membrane to drain water
collected by the drainage channels. Drainage of the water helps to prevent
deterioration of the insulating panels and water accumulation which may
provoke
overload problems.
[0004] Although such drainage structures are effective in removing
water
from flat roofs, they add significant complexity to the building structures
and hence,
increase costs making them unsuitable in many environments. As will be
appreciated,
alternative techniques to improve drainage in flat roofs are desired.
[0005] It is therefore an object of the present invention at least to
provide a
novel structural insulating panel and roof structure employing the same.
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Summary of the Invention
[0006] Accordingly, in one aspect there is provided a structural
insulating
panel for use in a flat roof structure comprising: upper and lower structural
layers,
said upper and lower structural layers being formed of material selected from
the
group comprising plywood, oriented strandboard and fire resistant board, said
upper
structural layer having an upper surface defining decking of said flat roof
structure on
which roofing material is to be applied; and an intermediate layer formed of
foam
material, said intermediate layer being sandwiched directly between and bonded
to
said upper and lower structural layers by adhesive, said intermediate layer
being
shaped such that said upper structural layer is sloped relative to a generally
horizontal
plane when said structural insulating panel is installed in a flat roof
structure, wherein
the longitudinal dimension of said structural insulating panel is selected so
that said
structural insulating panel spans at least one pair of adjacent rafters of
said flat roof
structure.
[0007] In one embodiment, the intermediate layer is shaped such that the
upper structural layer is sloped in multiple dimensions relative to the
horizontal plane.
The upper structural layer may slope generally linearly downwardly in
generally
orthogonal directions or may curve downwardly in different directions. In
another
embodiment, the intermediate layer is shaped such that the upper structural
layer
slopes generally linearly downwardly in a single direction.
[0008] In one form, each of the upper and lower structural layers may
have a
thickness in the range from about 1/8" to about 11/2". The intermediate layer
may
have a minimum thickness of about 1" and a maximum thickness of about 16".
[0009] According to another aspect there is provided a flat roof
structure
comprising a plurality of abutting structural insulating panels as described
above, each
structural insulating panel spanning at least a pair of adjacent rafters of
the flat roof
structure and defining an upper decking surface on which roofing material is
applied,
the structural insulating panels being configured such that the upper decking
surface is
non-horizontal thereby to promote drainage.
[00010/11] The structural insulating panels in one form are arranged at
least one of
end-to-end and side-to-side with adjacent structural panels carrying mating
formations. Sealant seals seams between the adjacent structural insulating
panels.
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Brief Description of the Drawings
[00012] Embodiments will now be described more fully with reference to
the
accompanying drawings in which:
[00013] Figure 1 is a top plan view of a flat roof structure employing
structural
insulating panels;
[00014] Figure 2 is a side elevational view of the roof structure of
Figure 1;
[00015] Figure 3 is an enlarged portion of Figure 2;
[00016] Figure 4 is a perspective view of a structural insulating
panel forming
part of the flat roof structure of Figure 1;
[00017] Figure 5 is a cross-sectional view of Figure 4 taken along line 5-
5;
[00018] Figure 6 is a cross-sectional view of Figure 4 taken along
line 6-6;
[00019] - 'Figure 7 is a top plan view of an alternative structural
insulating panel
for use in a flat roof structure;
[00020] Figure 8 is a cross-sectional view of Figure 7 taken along
line 8-8;
[00021] Figure 9 is a cross-sectional view of Figure 7 taken along line 9-
9;
[00022] Figure 10 is a top plan view of yet another structural
insulating panel
for use in a flat roof structure;
[00023] Figure 11 is a cross-sectional view of Figure 10 taken along
line 11-11;
[00024] Figure 12 is a cross-sectional view of Figure 10 taken along
line 12-12;
[00025] Figure 13 is an enlarged side elevational view of a portion of
adjacent
structural insulating panels showing an alternative joint; and
[00026] Figure 14 is an enlarged side elevational view of a portion of
adjacent
structural insulating panels showing yet another joint.
Detailed Description of the Embodiments
[00027] Turning now to Figures 1 to 3, a flat roof structure is shown
and is
generally identified by reference numeral 30. The flat roof structure 30
comprises a
plurality of abutting structural insulating panels 32 arranged in an array. In
this
embodiment, the array comprises six (6) rows and three (3) columns of panels
32.
Those of skill in the art will appreciate that the 6 x 3 array of panels 32 is
shown for
illustrative purposes only. The dimensions of the panel array can vary
significantly
depending on the overall size of the flat roof structure 30 and the dimensions
of the
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individual panels 32 in the array. The longitudinal dimension of each panel 32
is
selected so that each structural insulating panel 32 spans at least one pair
of adjacent
rafters 34. Typically, each structural insulating panel 32 will have a
lengthwise
dimension in the range of from about eight (8) feet to about twenty (20) feet
and a
widthwise dimension equal to about four (4) feet. Suitable fasteners (not
shown) such
as screws or nails are used to secure the structural insulating panels 32 to
the rafters
34.
1000281 The upper surfaces 36 of the structural insulating panels 32
define the
decking 38 of the flat roof structure 30 on which roofing (not shown) is
applied. The
structural insulating panels 32 are configured so that the decking 38 is
pitched in
multiple dimensions thereby to promote drainage towards the outer peripheral
edges
of the flat roof structure 30. The pitch in each dimension is typically
selected so that
it does not exceed 1/12". In the embodiment of Figure 1, the structural
insulating
panels 32 in column Cl, rows R1 to R3 and in column C3, rows R1 to R3 are
configured so that the flat roof structure 30 slopes linearly downwardly to
the right as
indicated by arrows 40 and slopes linearly downwardly from its central
longitudinal
axis 42 towards its peripheral side edge 44 as indicated by arrows 46. The
structural
insulating panels 32 in column Cl, rows R4 to R6 and in column C3, rows R4 to
R6
are configured so that the flat roof structure 30 slopes linearly downwardly
to the right
as indicated by arrows 40 and slopes linearly downwardly from its longitudinal
axis
42 towards its peripheral side edge 48 as indicated by arrows 50. The
structural
insulating panels 32 in column C2, rows R1 to R3 are configured so that the
flat roof
structure 30 slopes linearly downwardly to the left as indicated by arrow 52
and
slopes linearly downwardly from its longitudinal axis 42 towards its
peripheral side
edge 44 as indicated by arrow 46. The structural insulating panels 32 in
column C2,
rows R4 to R6 are configured so that the flat roof structure 30 slopes
linearly
downwardly to the left as indicated by arrow 52 and slopes linearly downwardly
from
its longitudinal axis 42 towards its peripheral side edge 48 as indicated by
arrow 50.
[000291 Turning now to Figures 4 to 6, one of structural insulating
panels 32 is
better illustrated. As can be seen, structural insulating panel 32 comprises
an
intermediate layer 60 sandwiched between and bonded to upper and lower
structural
layers 62 and 64 respectively by suitable adhesive. In this embodiment, the
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intermediate layer 60 is formed of expanded polystyrene (EPS) foam and
comprises a
core 70 typically having a thickness in the range of from about 1" to about
16", a top
skin 72 on the core 70 having a thickness of about 7/16" and a bottom skin 74
on the
core 70 having a thickness of about 5/8". The upper and lower structural
layers 62
and 64 are formed of a suitable structural material such as for example
plywood and
have a thickness generally in the range of from about 1/8" to about 11/4". The
thicknesses of the upper and lower structural layers 62 and 64 are selected to
give the
flat roof structure 30 its desired fire rating.
[00030] The core 70 varies in thickness to give the structural
insulating panel
32 its desired pitch. As a result, the upper structural layer 62 which
overlies the top
skin 72 of the intermediate layer 60 conforms to the orientation of the
intermediate
layer and thus, provides the sloped upper decking surface onto which the
roofing is
applied. One minor side of the lower structural layer 64 has a groove 80
formed
therein and the opposite minor side of the lower structural layer 64 has a
tongue 82
formed thereon. The groove 80 is shaped to receive a tongue formed on an
adjacent
structural insulating panel 32 and the tongue 82 is shaped to be inserted into
the
groove formed in another adjacent structural insulating panel 32. Similarly if
desired,
one major side of the lower structural layer may be provided with a groove and
the
opposite major side of the lower structural layer may be provided with a
tongue.
[00031] Looking back to Figure 3, one of the seams 90 between two adjacent
structural insulating panels 32 is shown. As can be seen, the tongue 82 on the
lower
structural layer 64 of one structural insulating panel is received in the
groove 80
formed in the lower structural layer 64 of the other structural insulating
panel.
Adhesive caulking 92 is applied to the tongue 82 and/or groove 80 prior to
insertion
of the tongue into the groove to secure the lower structural layers of the
adjacent
structural insulating panels 32 together. A sealant 94 such as for example, a
foam seal
or sill seal gasket, is used to fill any gaps between the intermediate layers
60 and
upper structural layers 62 of the adjacent structural insulating panels at the
seam 90.
[00032] In the above embodiment, the structural insulating panels 32
of the flat
roof structure 30 are configured so that the flat roof structure 30 slopes
linearly
downward in two different directions. Those of skill in the art will
appreciate
however, that other structural insulating panel configurations can be used in
flat roof
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structures 30 to promote drainage. For example, turning now to Figures 7 to 9,
another embodiment of a structural insulating panel for use in a flat roof
structure is
shown and is generally identified by reference numeral 132. Similar to the
structural
insulating panel 32, structural insulating panel 132 also comprises an
intermediate
EPS layer 160 sandwiched between upper and lower structural layers 162 and 164
respectively. In this embodiment, rather than sloping linearly downwardly in
two
different directions, the core 170 of the intermediate layer 160 has a
parabolic shape
and thus, curves downwardly from its center in all directions towards the
edges of the
intermediate layer.
1000331 Figures 10 to 12 show yet another embodiment of a structural
insulating panel 232 for use in a flat roof structure. Similar to the
structural insulating
panels 32 and 132, structural insulating panel 232 comprises an intermediate
EPS
layer 260 sandwiched between upper and lower structural layers 262 and 264
respectively. In this embodiment, the core 270 of the intermediate layer 260
slopes
linearly downwardly in only one direction.
[00034] Although the embodiments described and shown above show
adjacent
structural insulating panels 32 as comprising mating formations in the form of
tongues
and grooves, those of skill in the art will appreciate that alternative joints
between
adjacent structural insulating panels can be used. For example, Figure 13
shows
adjacent structural insulating panels 32 interconnected via an overlap joint
and Figure
14 shows adjacent structural insulting panels interconnected via a butt spline
joint.
1000351 Although dimensions for the structural insulating panels and
components therefor, are provided above, those of skill in the art will
appreciate that
the dimensional information is exemplary. Depending on the environment in
which
the structural insulating panels are being deployed, the overall dimensions of
the
structural insulating panels and the dimensions of the panel components may
vary
from those discussed above.
[00036] In the embodiments described above, the upper and lower
structural
layers 62 and 64 are described as being formed of plywood. Those of skill in
the art
will appreciate that the upper and lower structural layers may be formed of
other
suitable structural material such as for example OSB, metal sheet, fire
resistant board
etc. Also, the intermediate layer 60 need not be formed of EPS. Other foam
material
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such as for example urethane foam, polyurethane foam, isocyanurate foam etc.
or
other suitable non-foam material such as for example honeycomb board may be
used.
[00037] While particular examples of structural insulating panels that
provide
pitched upper decking surfaces are described and illustrated above, those of
skill in
the art will appreciate that the structural insulating panels may take on
other
orientations to promote drainage. Of course, if desired the structural
insulating panels
can be used on wall structures for structural and/or decorative purposes.
[00038] Although embodiments have been described above with reference
to
the drawings, those of skill in the art will appreciate that variations and
modifications
may be made without departing from the scope thereof as defined by the
appended
claims.
